question on welding cast iron

[revkev6]

I have a "Junk" 1947 ford flathead engine sitting on my garage floor that I grabbed for free last weekend. at some point in it's life it sat with water in the jackets and froze. it's got a crack in the oil pan rail. not an uncommon thing with these motors. It's free to me and my son and I are taking it apart for a learning experience. I wouldn't mind taking a shot at welding up the crack.

I've heard a few different processes for welding cast iron:

55 or 99 nickel rod
308 stainless rod
*insert your magic rod here* brand of cast iron magic
tig brazing with silicon or AL. bronze rod.

given that this is in the oil pan/cooling flow location it won't see extreme heat and the stress that caused the crack was from frozen water... so that's not an issue.

what are your thoughts and successes with such a fix?? I'm not going to be out anything other than the cost of the rod I used and my time if it goes pare shaped. perfect practice job, and if it works that's a bonus.

pictures to follow